The Mass Spectrograph & Average Atomic Mass

Inventor

• Francis William Aston won the 1922 Nobel Prize in Chemistry for his work in mass spectrometry

The First Mass Spectrograph

How Does it Work?

Schematics of a simple mass spectrometer with sector type mass analyzer. This one is for the measurement of Carbon dioxide isotope ratios (IRMS) as in the carbon-13 urea breath test

The Detector

A continuous dynode particle multiplier detector.

The Data

Mass Spectrograph of a protein

The Data as a Bar Graph

The Modern Mass Spectrograph

TEACHER IN THE LAB

NOAA Southeast Fisheries Science Center

Virginia Key, FloridaSummer 2009 & 2010

Mark Silverman, Teacher in the LabTrika Gerard, Principle Investigator

Estrella Malca, Lab Manager

The Program

• Teacher in the Lab (TIL).

The Research

Part II: Otolith Chemistry

Otoliths• What are they?• Where are they found? • Why are they important to fisheries biologists?

Objectives

• Examine relationships between otolith isotope signature and length within same species.

• Compare signatures between species where lengths overlap.

• Examine variability in signature within fish of a similar size.

• Examine variability in signature from 2009 to 2010 in Lutjanus synagris of similar sizes.

• Examine signature variation in Ocyurus chrysurus in similar size fishes from 2010.

Otolith chemistryOtolith chemistry

• Fish take up trace elements Fish take up trace elements by drinkingby drinking

• Certain elements are Certain elements are incorporated into the incorporated into the matrix of otoliths with matrix of otoliths with growth growth

• These elements become These elements become fixed within the otolith as fixed within the otolith as layers are laid downlayers are laid down

Slide by: M. R. Lara, et al, 2004

Methods• 10 L. synagris were selected based on size range and

collection date from both 2009 and based on size range from 2010 (there was a single collection date in 2010). The total sample size was 20 fish.

• 10 O. chrysurus were selected from each year 2009 and 2010. There was less overlap in sizes available between these collections. The total sample size was 20 fish.

• Otoliths were extracted, prepared, and examined by mass spectrograph for stable isotopes of oxygen (18O:16O) and carbon (13C:12C).

L. synagris O. chrysurus

• Otoliths are removed Otoliths are removed using acid washed using acid washed glassglass instruments instruments under clean hoodunder clean hood

• All tissue is removed, All tissue is removed, otoliths washed in otoliths washed in ultraultra--pure waterpure water

• Otoliths are dried, Otoliths are dried, stored and then stored and then transported to AMOL transported to AMOL and run through the and run through the mass spectrometermass spectrometer

Sample PreparationSample Preparation

Portion of slide by: M. R. Lara, et al, 2004

How How ??

1.1. Whole otoliths are crushedWhole otoliths are crushed2.2. Molecules broken down to Molecules broken down to

elementselements3.3. Stable isotopes are determined Stable isotopes are determined

by weightby weight

Mass SpectrometryMass Spectrometry

Data and Analysis

Site

Sample ID

Species

SL (mm

)Collect

ed Pulled

Otoliths

Pulled

Physically

Available SIL

Otolith

Weight (g)

% of otolith used

Weight of Otolith used

Amt. of Bleach added (mL)

Carbon

Oxygen

US Virgin

Islands                            

BBBB:058

L. synagri

s 5828-

Feb-0930-Jun-

10 2    0.0139 100

0.0139      

BBBB:059

L. synagri

s 8824-Jan-

0930-Jun-

10 2    0.0237 50

0.0119      

BBBB:060

L. synagri

s 5024-Jan-

0930-Jun-

10 2    0.0065 100

0.0065      

BBBB:061

L. synagri

s 4024-Jan-

0930-Jun-

10 2    0.0042 100

0.0042      

BBBB:062

L. synagri

s 7116-

Feb-0930-Jun-

10 2    0.0186 50

0.0093      

BBBB:063

L. synagri

s 7816-

Feb-0930-Jun-

10 2    0.0209 50

0.0105      

BBBB:064

L. synagri

s 8316-

Feb-0930-Jun-

10 1    0.0296 50

0.0148      

BBBB:065

L. synagri

s 7916-

Feb-0930-Jun-

10 2    0.0290 50

0.0145      

BBBB:066

L. synagri

s                        

BBBB:067

L. synagri

s                        

BBBB:068

L. synagri

s                        

BBBB:069

L. synagri

s                        

BBBB:070

L. synagri

s                        

BBBB:071

L. synagri

s                        

BBBB:072

L. synagri

s                        

BBBB:073

L. synagri

s                        

BBBB:074

L. synagri

s                        

BBBB:075

L. synagri

s                        

BBBB:076

L. synagri

s                        

BBBB:077

L. synagri

s                        

                             

                             

                             

Conclusions• Red L. synagris • Blue O. chrysurus

Conclusions• Red 2009• Green 2010

• Red 2009

• Purple 2010

Conclusions

ReferencesBoehlert, G.W. and B. C. Mundy. Roles of Behavioral and Physical Factors in Larval

and Juvenile Fish Recruitment to Estuarine Nursery Areas. Southwest Fisheries Center Honolulu Labortarory, National Marine Fisheries Service. http://swfsc.noaa.gov/publications/CR/1988/8815.PDF

Strydom, Nadine A. 2008. Utilization of shallow subtidal bays associated with warm temperate rocky shores by the late-stage larvae of some inshore fish species, South Africa. South African Institute for Aquatic Biodiversity. http://www.bioone.org/doi/pdf/10.3377/1562-7020-43.2.256

Campana, Steven E. 1999. Chemistry and composition of fish otoliths: pathways, mechanisms, and applications. Marine Ecology Progress Series,188:263-297.

Radtke, R.L., W. Showers, E. Moksness, and P. Lenz. 1996. Environmental information stored in otoliths: insights from stable isotopes. Marine Biology, 127: 161-170.

Note:• Percent = out of 100 %

• Relative abundance = out of one whole

• Average Atomic Mass – the average mass of all the naturally occuring isotopes of an element expressed in atomic mass units.

The Mass Spectrograph for the common isotopes of Boron

The relative sizes of the peaks gives you a direct measure of the relative abundances of the isotopes. The tallest peak is often given an arbitrary height of 100 - but you may find all sorts of other scales used. It doesn't matter in the least.You can find the relative abundances by measuring the lines on the stick diagram.In this case, the two isotopes (with their relative abundances) are:

boron-10 18.70%, 10.013 g/molboron-11 81.30%, 11.009 g/mol

Sample Problems• What is average atomic mass of Lithium if 7.42% exists

as 6Li (6.015 g/mol) and 92.58% exists as 7Li (7.016 g/mol)?

• Two isotopes of silver are found using the mass spectrograph. Silver – 107 has an atomic mass of 106.91 amu and an abundance of 51.86 %. The second isotope has an abundance of 48.14 %, but its atomic mass was unable to be determined. What is the atomic mass and the mass number(identity) of this isotope?